title: Hypoxic resistance of hypodermically transplanted pancreatic islets by using cell-absorbable antioxidant Tat-metallothionein.
abstract: Subcutaneous site is ideal for clinical islet transplantation because it has the advantage of simple operation procedure under local anesthesia and can be biopsied when needed. However, the transplantation outcomes at subcutaneous site have been disappointing due to hypoxia-induced oxidative stress by poor vascularization. We hypothesized that subcutaneously transplanted islets would have hypoxia resistance by using internalization of metallothionein (MT), an antioxidant scavenging enzyme, which was mediated by fusion between MT and cell penetrating Tat peptide. The Tat-MT was dose-dependently transduced into islets without any damage. Tat-MT-treated islets could be protected from oxidative stress induced by intracellular nitric oxide donor, sodium nitroprusside (SNP). When Tat-MT-treated islets were subcutaneously transplanted into diabetic nude mice, they normally controlled the blood glucose levels without severe fluctuation (median survival time (MST): >30 days), whereas most untreated islets were rejected (MST 17 days). From the intraperitoneal glucose tolerance test 5 days after posttransplantation, glucose responsiveness of Tat-MT-treated islets was similar to that of normal healthy mice, while untreated islets had delayed glucose responsiveness. From the results of immunohistochemical stain, Tat-MT-treated islets had strong anti-insulin positive cells and lower anti-HIF-1α positive cells. However, untreated islets had rare anti-insulin positive cells and strong anti-HIF-1α-positive cells. Collectively, these findings demonstrated that Tat-MT delivery into islet could offer a new strategy for successful islet transplantation under subcutaneous space.
authors.affiliation: Department of Bioengineering, College of Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Hae Song
authors.initials: HS
authors.lastname: Jung
authors.forename: Kwang Suk
authors.initials: KS
authors.lastname: Lim
authors.forename: Min Jun
authors.initials: MJ
authors.lastname: Kim
authors.forename: Yong Hwa
authors.initials: YH
authors.lastname: Hwang
authors.forename: Changhun
authors.initials: C
authors.lastname: Yoo
authors.forename: Yong-kyu
authors.initials: YK
authors.lastname: Lee
authors.forename: Yong-Hee
authors.initials: YH
authors.lastname: Kim
authors.forename: Dong Yun
authors.initials: DY
authors.lastname: Lee
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D015696:Gene Products, tat / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D005947:Glucose / Q000378:metabolism; D005951:Glucose Tolerance Test; D006801:Humans; D000860:Hypoxia / Q000378:metabolism / Q000517:prevention & control*; D007328:Insulin / Q000378:metabolism; D007515:Islets of Langerhans / Q000378:metabolism; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D008668:Metallothionein / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D051379:Mice; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D015696:Gene Products, tat; D007328:Insulin; D011993:Recombinant Fusion Proteins; D008668:Metallothionein; D005947:Glucose
keywords: Hypoxia; Metallothionein; Pancreatic isle; Protein delivery; Subcutaneous transplantation; Tat peptide